The present invention relates, in general, to integrated vacuum microelectronic devices, and more particularly to the fabrication of microelectronic sources and source arrays consisting of silicon or silicide field emitters and multiple planar electrodes.
The field of vacuum microelectronics grew out of the application of microfabrication technology, which was developed for solid-state electronic devices, to vacuum devices. Early work focused on the fabrication of field emitter arrays, but progress in fabrication technology has let to the investigation of a variety of new devices in high-speed electronics, flat panel displays, sensors including field emission and other tunneling sensors, and electron optics including microelectrostatic lenses and microcolumns.
The processes and devices developed so far all suffer from the crucial limitation that they are non-planar. For example, arrays of electronoptical microcolumns have been proposed as a massively parallel approach to the throughput bottleneck in electron beam lithography. However, previous implementations have required a complex assembly of separately fabricated pieces with resulting difficulties in alignment which limit the achievable parallelism. These difficulties limit designs with vertical field emitters to a single gate or extraction electrode, with additional electrodes having to be located on additional substrates. Alternatively, lateral emitter designs have been developed to allow multiple electrodes, but these are limited in feature size by lithography technology.